Numerical study of effusion cooling flow and heat transfer

An isothermal and non-isothermal numerical study of effusion cooling flow and heat transfer is conducted using a Reynolds-averaged Navier–Stokes (RANS) approach. A Reynolds stress transport (RST) turbulence model is used to predict the flow field of a staggered array of 12 rows of effusion holes, each hole inclined at 30° to the flat plate. The Reynolds number based on the hole diameter and jet exit velocity is 3800. The blowing ratio in both studies is 5. A conjugate heat transfer approach is adopted in the non-isothermal simulation. For the isothermal case, the RST model is shown to be capable of predicting the injection, penetration, downstream decay and lateral mixing of the effusion jets reasonably well. In addition, the numerical model captures the existence of two counter-rotating vortices emanating from each hole, which causes the entrainment of combustor flow towards the surface of the plate at the leading edge and downstream, influences the mixing of accumulated coolant flow, providing a more uniform surface temperature across the plate. The presence and characteristics of these vortices are in good agreement with previously published research. In the non-isothermal case, the laterally averaged cooling effectiveness across the plate is under-predicted but the trend conforms to that exhibited during experimentation.